In a conventional manner, an aircraft is fitted with a flight management computer used by the pilot for example for computing a reference path based on a flight plan.
It should be noted that a flight plan comprises a sequence of segments. Each segment is defined based on maneuvering instructions that the aircraft must comply with to go from one point to another; these instructions are defined thanks to mandatory and/or optional parameters that are also sometimes described as lateral or vertical constraints. These instructions are listed in a navigation database of the computer.
The reference path from the airport of departure to the destination airport is computed based on these segments which include lateral and vertical constraints, based on constraints of altitude, speed and time, and on the context of the aircraft such as the consumption, the weight of the aircraft, the winds, the temperature, the passenger comfort rules (the banking angle, the load factor), etc.
But, for this reference path to be a path that can be flown by the aircraft, certain lateral or vertical constraints are not complied with or not very closely.
The computer tells the crew the vertical constraints that are not complied with. But neither the crew nor the computer verify that the path obtained complies with the lateral constraints.
An important object of the invention is therefore to help to overcome this disadvantage.